Strain insulator



L. STEINBERGER.

STLRAINJNSULATOR.

APPLICATION FILED DEC. .10, 1918.

1 ,406,698, Patented Feb. 14, 1922.

WITNESS 7/ LOUIS STEINBERGER, F BROOKLYN, NEW YORK.

STRAIN INSULATOR.

Specification of Letters Patent.

Patented Feb. 14, 1922.

Application filed December 10, 1918. Serial No. 266,052.

To all whom it may concern:

Be it known that I, LOUIS STEINBERGER, a citizen of the United States, and a resident of the borough of Brooklyn, county of Kings, State of New York, have invented certain new and useful Improvements in Strain Insulators, of which the following 7 is a'specification.

My invention relates to strain insulators provided with means for causing the insulator to flash over between the strain member connected to the line and said means and the strain member connected to ground.

One of the objects therefore of my invention is to provide a strain insulator with a conducting member normally inactive but so situated as to receive the current under abnormal conditions to carry the same through the central portion of the insulator and are across to the terminals or strain members thus causing the current to spark across rather than break down the insulator internally. I

Another object of the invention is to provide a normally inactive electrical conductor within the body of an insulator to act as a redistributor of 'the electrical stresses thereby improving the value of the insulator.

Other objects will appear from the subjoined specification and claims.

Referring to the drawings:

Fig. 1 is a vertical section through the central portion of a strain insulatorembodying my invention, theparts of the insulator being shown in elevation.

Fig. 2 is a similar-view of a strain insu- .lator illustrating a modified construction also embodying my invention.

.It is well known that in actual operation the insulating material especially at the central portion of the insulator becomes heated and thereby the insulator loses in eiliciency both electrically and mechanically. If the heat is permitted to continue for a certain period of time the destruction of the insulator will follow.

The present invention is applicable to all insulators and especially to strain insulators, and the insulator structure is so formed that the central portion thereof which heats rapidly, is provided with an electrical conductor extending therethrough and protruding therefrom which will permit the ready flow outwardly from the center of the insulator body of the heat generated since metal is a much better=conductor of heat than the insulating material, the electric conductor also providing a conductive path through the insulator for the flashover current between the strain members.

I will now describe the preferred form of insulator embodying the invention hereinabove referred to.

In the drawings, in which the same reference character indicates the same part in the several views:

A is an insulator'body which maybe formed of any suitable insulating material, but I prefer to use the insulating material well known in the art as electrose.- B is the integral strain member made of metal and C is a two part strain member also made of metal which is provided with the well known means for connecting the two parts together, namely,.one of the projecting ends 10 of the two part strain member is provided with screw-threads which engage the screw threads in the, socket 11 of the removable portion 12 ofthe two part strain member C. The sleeve 13 is screw-threaded to the other projecting end 10 of the embedded portion of the strain member and to the abutting end 14 of the removable portion of the strain member. This means of connecting the two part insulator so that said' parts may also be removed, is well known in the art and therefore does not require a more specific description.

The strain members are also of the type invented by me and consist of bridge members embodying ring shaped portions 20 and 30, said rings bridging the upright or leg portions respectively of the two strain members. The body portion of the insulator is molded about the strain members after they have been centered with respect to each other by bringing the ring portion of each insulator opposite each other so that the rims of the ring portions will be in direct alignment, leaving a uniform body of insulating material between the rings.

The body of insulating material is molded about the assembled interlocked strain members as shown, so as to form the shape shown in the drawings in which the insulating material is molded around the leg portions of each strain member to form projections 25. 26. 27 (the fourth not shown in the drawings). and there is also a central radially projecting flange 50 extending from the insulator body. Integral flanges 21 and 22 extend from the legs of the embedded A centrally disposed rod 40 provided with globular shaped ends 41 and 42 is positioned in a straight line extending through the ring portions of the strain members and so arranged that when the insulator body is molded into the shape shown, around and -ilhistration in Fig. 2.

The tube 60 and the rods 62 and assembled in the position shown in Fig. 2,

about the strain members, the rod 40 will be molded into the central portion of the insulator body, the globular ends 41 and 42 only projecting out therefrom. I

As will be readily understood, this metallic rod does not normally carry any electric current but should the voltage become high enough, the rod will cause the insulator to flash over between the strain members and the ends of the metal rod, thereby protecting the insulator against puncture.

Referring to Fig. 2 showing a modified form of my invention, the insulator body and the strain members are the same as heretofore described. with respect to the embodiment of my invention as shown in Fig. 1, the difference being that instead of a solid metal rod, I provide a metal tube 60 in a position similar to that assumed by the metal rod 40 as shown in Fig. 1. This metal tube is molded within the insulator body centrally thereof and is surrounded by the ring portions of the strain members in the same relative pos1t1on as shown in Fig. l

with respect to the ring portions of thestrain members and the metal rod 40. The tube 60 is as stated above, molded into its position within the body of the insulator during its manufacture and extends outwardly only to the top and bottom surface of the insulator body. The tube is screwthreaded at 61 within the inner surface thereof; Two rods 62 and 63 provided with globular shaped ends 64 and 65 and with screw-threaded shanks 66 and 67 are adjustably secured respectively to each end of the tube, the screw-threads of each-\of the shanks engaging the screw-threads on the inner wall of the metal tube so that the positions of the rods may be adjusted with respect to each other, as will be readily understood from this description and from the 63 when form in efi'ect so far as electrical carrying capacity is concerned, a solid rod of metal and as herein described this electrical con- I claim asnew and desire to secure by Letters Patent is: r

1-. An insulator comprising a body of 1nsulating material, strain members provided with centrally disposed'portions embedded therein, the central portions of the strain membersbeing ring shaped, said ring portions being situated oppositeto each other,

an electrical conductor passing through the body of the insulator and also through the ring portions of the strain members, the sai, electrical conductor being provided with exposed globular projections at each end thereof.

2. An insulator comprising a body of insulating material, strain members provided with centrally disposed portions embedded therein, the central portions of thestrain members being ring shaped, said ring portions situated opposite to each other, an electrical conductor passing through the body of. the insulator and also through the ring portions of the strain members, the said electrical conductor being provided with an exposed globular shaped end.

3. An insulator comprising a body of insulating material, strain members provided with centrally disposed portions embedded therein, said body being provided with an electrical conducting member passing therethrough, said electrical conducting member also passing through the central portions of the strain members and means for adjusting the length of said conducting member.

4. An insulator comprising a body of insulating material, strain members provided with centrally disposed portions embedded therein, said body being provided with an electrical conducting member passing therethrough, said electrical conducting member of the strain members situated opposite to conducting memb er at each other, the said central portlons being ring shaped, and an electrical conductor passing through the body of the insulator and also through the ring portions of the strain members, said conductor consisting of a metallic sleeve molded to the insulator body provided with screw threads on the inner wall thereof, screw threaded plugs adjustably secured to the centrally arranged sleeve.

6. An insulator comprising a body of in- I I sulating material, interlocking strain memsleeve.

bars provided with centrally disposed portions molded therein, the central portions of the strain members situated opposite to each other, the said central portions being ring shaped, and an electrical conductor passing through the body of the insulator and also through the ring portions of the strain members, said conductor consisting of a metallic sleeve molded to the insulator body, provided with screw threads on the inner wall thereof, screw threaded plugs provided with globular shaped ends adjustably secured to the centrally arranged 7. An insulator comprising a body of insulating material, strain members provided adjusting the length of said conducting member.

8. An insulator comprising a body of insulating material, strain members provided with centrally disposed portions embedded therein, said body of insulating material having an electrical conducting member passing therethrough, said conducting member also passing through the central por tions of.the strain members and means for adjusting the length of said conducting member at each end thereof.

9. An insulator comprising a body of insulating' material, strain members provided with centrally disposed portions embedded therein, said body of insulating material having an electrical conducting member passing therethrough, said conducting member having globular shaped ends and also passing through the central portions of the strain members and means for adjusting the length of the said conducting member at each end thereof.

In witness whereof, I have hereunto set my hand at the borough of Manhattan, city and State of New York, this fifth day of December, 1918.

LOUIS STEINBERGER.

In presence of- ZITA M. GRAHAM. 

